1. Field of the present invention
The present invention relates to a high frequency switch module that switches a plurality of kinds of high frequency signals to transmit and receive the signals.
2. Description of the Related Art
High frequency switch modules have been variously designed to transmit and receive a plurality of communication signals with individual frequency bands using one antenna. For example, in Japanese Unexamined Patent Application Publication No. 2003-87150, a high frequency composite switch module is disclosed which includes an SPnT type (n is a positive number) switch IC and a laminated body on which the switch IC is mounted.
As such high frequency switch modules are used for radio communication apparatuses, such as mobile phones, it is necessary to increase the power of the transmission signal in such an apparatus. Thus, it is necessary to increase the power resistance of a circuit on the transmission side. Since the reception signal received by an antenna has a signal level less than that of the transmission signal, it is not necessary to increase the power resistance as much as the circuit on the transmission side. For a communication system, there are cases in which a terminal for both transmission and reception is used. However, in such cases, the power resistance as high as a circuit on the transmission side used only for transmission is not necessary.
For this reason, in the existing switch IC, a transmission switch circuit connecting an antenna terminal (common terminal) and a transmission terminal to each other, a reception switch circuit connecting an antenna terminal (common terminal) and a reception terminal to each other, and a transmission and reception switch circuit for transmission and reception have different structures, according to specifications of radio communication apparatuses, such as mobile phones. With such a configuration, an external connection terminal of the switch IC is predetermined to be used with any one of the antenna terminal (common terminal), the transmission terminal, the reception terminal, and the transmission and reception terminal.
Recently, as mobile phones get smaller, it is necessary to reduce the size of high frequency switch modules. Meanwhile, mobile phones must be provided with a multi-band system, to cope with various communication systems such as GSM, WCDMA, and UMTS, and have to be provided with a transmission terminal and a reception terminal, or a transmission and reception terminal for all of the communication systems, according to specifications.
For this reason, the design and production of a switch IC are individually performed whenever specifications are changed, and thus, high costs and large amounts of time have been required. In addition, for the laminated body on which the switch IC is mounted, changes in the design of the mounting surface, accompanying changes in the design of internal structure thereof, and production of the laminated body based on such changes in the design must be performed as the switch IC changes. High costs and large amounts of time have been expended on these factors.